How Whole-Body Cryotherapy Works

Cryokiller

In July 2015, a woman walked into Rejuvenice, a medical spa in Henderson, Nevada, and prepared to open up shop for the day. While checking on a cryotherapy chamber she discovered to her surprise that it was already on. She turned it off and let the mist of nitrogen gas clear before opening it up.

Lying on the floor of the chamber was the body of her colleague, Chelsea Ake-Salvacion. Ake-Salvacion was not just dead; she had been frozen completely solid.

What had happened? Skeptics had been questioning the efficacy of cryotherapy, but now it looked as though it could be dangerous, even lethal.

Ake-Salvacion also worked at the spa and was a cryotherapy enthusiast and proponent. She made regular use of the cryotherapy chamber, firmly believing in its beneficial health effects. She also knew that staying too long in the chamber could be dangerous. Exposing the body for more than a few minutes to temperatures colder than the most frigid temperatures ever recorded on Earth is asking for trouble.

Ake-Salvacion's cellphone was found on the floor near her body. Investigators speculate she was using her phone in the chamber, dropped it and lost consciousness when she went to pick it up. After that, she would have frozen. But why would she have passed out?

Nitrogen makes up 78 percent of the air we breathe, which is why many people assume that it's harmless. But that's true only if it's mixed with the right quantity of oxygen. Humans are happiest when we're breathing around 20.9 percent O2. Below 16 percent, the pulse starts racing, confusion sets in and we lose coordination. Permanent heart damage can result when breathing air with just 12.5 percent of the good stuff. And once oxygen levels drop below 10 percent we pass out and die [source: CSB].

During sessions in a cryotherapy chamber, your head stays safely above the gas, but in bending down, Ake-Salvacion would have submerged her head and possibly breathed in too much nitrogen, causing her to pass out. Since she was alone in the spa and nobody was monitoring her, there was no escape once she lost consciousness. In fact, the coroner's report found that she died not of freezing, but of asphyxiation [source: Women in the World].

The dangers of nitrogen

Nitrogen is used for many industrial purposes, but that doesn't mean it's safe. An investigation conducted by the U.S. Chemical Safety and Hazard Board (CSB) back in 2002 found that there were 80 industry-related deaths from nitrogen asphyxiation in the previous decade [source: CSB].